Pump

ABSTRACT

A pump actuated on its drive stroke manually, mechanically, or by fluid pressure and on its return stroke by relaxation of a compressed elastomer tube. The pump is adapted for axial pumping flow and, when fluid operated, may be glandless.

C Umted States Patent 1 1 3,583,836

[72] Inventor Stanley F. Evans [50] Field of Search 103/148, Coppeleye, Knowl, Cranham, near 152,44 D; 230/160, I62; 417/394, 472, 473 Gloucester. England 1211 Appl. N0. 776,465 1 References Cited [22] Filed Nov. 18, 1968 UNITED STATES PATENTS I 1 Pawmed 1,797,533 3/1931 Stokes 103/152x 1 Asslsnee Fluld Trust" Limited 2,785,852 3/1957 Bramming 230/160 PP smudicloumwrshinilzngland 2,830,757 4/1958 Romanoff 230/162 Priority 1 9 2,889,781 6/1959 Thompson 103/148x [33] Great Britmn [31] 3 3 Primary Examiner-Robert M. Walker AttorneyNorris 8L Bateman PUMP ABSTRACT: A pump actuated on its drive stroke manually, 17 Cl i 2 D mechanically, or by fluid pressure and on its return stroke by rawmg relaxation of a compressed elastomer tube. The pump is [52] US. Cl 417/394 adapted for axial pumping flow and, when fluid operated, may [5 l] Int. Cl F04b l7/ 00 be glandless.

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INVENTOR STANLEY FREDERICK EVANS BY gamma n PUMP The invention relates to a pump.

More particularly, the invention relates to a reciprocating pump of the kind having an actuating stroke and a return stroke; where, in the actuating stroke, the pumping element is driven manually, mechanically, pneumatically or hydraulically whilst energy is stored in a resilient means and, in the return stroke, the stored energy is released to return the pumping element.

lt is an object of the present invention to provide a pump of the kind described of single construction and of improved performance and endurance.

To this end the invention provides a pump comprising a main chamber having an inlet port and an outlet port each including a nonreturn valve and a tube ofelastomer whose ends are in sealing engagement with a fixed surface of the chamber and with a slidable compression plate respectively, the pump being arranged so that in a pumping cycle the compression plate is first acted upon by an external source of energy to compress the tube lengthwise and is then returned on release of the external source of energy by the relaxation of the tube.

Embodiments of the invention will be described with reference to the accompanying drawings in which:

FIG. 1 is an axial section of a fluid-operated pump according to the present invention, and

FIG. 2 is an axial section of a manually operated pump according to the present invention.

The pump shown in FIG. 1 is of circular cross section and is adapted to be mounted in the line of flow of the fluid to be pumped so that the direction of flow is undisturbed.

The pump has upstream and downstream bell-shaped end walls and 11 between which central sections 12 of the pump are located and held by six tie rods 13 passing through the end walls.

The upstream end wall 10 has a central conduit 14 forming an inlet port for the entry of the fluid being pumped which in cludes a nonreturn valve, preferably in the form of a valve member 15 which is urged against the downstream mouth of the conduit by a weak spring 16 attached to a fixed arm 17 within the end wall cavity.

The downstream wall 11 has a central conduit 18 for the exit of the fluid being pumped. A valve member 19 is urged against the downstream side of a central orifice 20, forming an outlet port, in a disc 21 extending across the end wall 11 by a weak spring 22 attached to a fixed arm 23 within the end wall cavity.

Each central section 12 includes an outer tube 24 having an inwardly directed flange 25 at its downstream end, an inner tube 26 having an outwardly directed flange 27 at its downstream end and coplanar with the outer flange and an annular cover plate 28 in sealing contact with the upstream end of both tubes. The outer diameter of the cover plate is equal to that of the outer tube and the plate has shoulders 29 near its outer periphery which match abutments 30 on the outer tube and in the outer tube of the adjacent section to ensure accurate radial alignment. The inner periphery of the cover plate is welded to the upstream end of the inner tube.

Within the annular activity formed by the tubes and cover plate there is an annular compression plate 31 which is slidable axially with a clearance between it and the adjacent tube walls. A cylinder or tube 32 of elastomer of rectangular cross section is retained between projecting rings 33 on the surface of the compression plate opposite the flange 27 of the tube 26. A similar cylinder 34 is retained between rings 35 on the flange and the adjacent surfaces of the blocks are fixed to opposite sides of an interposed rigid retaining ring 36. Elastomeric cylinders 37 and 38 of similar cross section are retained in rings 39 and 40 in the outer flange 25 and the adjacent surface of the compression plate respectively and are separated by an interposed rigid retaining ring 41. The dimensions of the cylinders are arranged so that in their relaxed state the compression plate just touches part of the cover plate.

The central sections 12 are disposed end to end between the end walls 10 and 11 so that a main chamber for the fluid to be pumped is formed including an axial portion 42 of fixed volume within the inner tubes and peripheral portions 43 of variable volume between each set of inner and outer cylinders of elastomer. Auxiliary chambers 44 of variable volume for the operating fluid are formed in the gap between the compression and cover plates and between the cylinders of elastomer and the tube walls.

Each auxiliary chamber 44 is connected through a bore 45 in the outer tube wall 24 to a common delivery pipe 46 leading from a control valve 47 which is connected to an operating fluid source 48, preferably an air supply, and to an exhaust 49.

The operation of the control valve is determined by the operation of an electrical or pneumatic switch 50 which, in turn, is operated by contacts 41 and 52 on a sliding rod 53 attached to the compression plate of the central section furthest downstream and passing axially through the adjacent cylinders of elastomer and the end wall.

The operating cycle of the pump will now be described."

ln the drawings, the pump is shown at the end of an intake stroke but with both valves closed. All the cylinders of elastomer are in their relaxed positions and the main chamber 42, 43 therefore has a maximum volume whereas the auxiliary chamber 44 has a minimum volume. On actuation of the switch 50 by the contact 51 the control valve 47 is operated to admit air pressure to the auxiliary chambers. The air acts on the compression plate 31 and causes it to move axially to compress the elastomeric cylinders 32, 34, 37 and 38 and expand the chamber. This expansion reduces the volume of the peripheral portions 43 of the main chamber and the fluid in the main chamber is pumped out past the outlet valve member 19 and through the outlet conduit 18.

At the end of the delivery or exhaust stroke the contact 52 actuates the switch 50 so that the control valve cuts OK the air supply and connects the auxiliary chambers through an exhaust to the atmosphere. As the air is exhausted the energy stored in the elastomer cylinders causes them to return the compression plates increasing the volume of the peripheral portions of the main chamber. The outlet valve member closes and the inlet valve member 15 opens to admit fluid from the inlet conduit 14.

The rings 36 serve to retain the elastomer radially during operation. Suitable materials for use as elastomer are natural or synthetic rubbers, PTFE, neoprene, polyurethane and silicone rubbers. The cylinders 32 and 34, separated by ring 36 form units of an inner elastomeric tube. Similarly, the outer cylinders form units of an outer elastomeric tube. Whilst elastomeric tubes comprising a series of two cylinders are described and shown with respect to each central section it is to be understood that each section may have elastomeric tubes formed of a series of more than two unit cylinders, each cylinder being separated from its neighboring cylinder by a rigid retaining ring. In particular the three central sections shown could be replaced by one section having inner and outer elastomeric tubes comprising series of about nine cylinders each. Such a pump would be especially suitable for pumping compressible fluids, such as gases, as a solid tube (not shown) could be inserted in the peripheral portion 43 of the main chamber so as to fill most of its volume when the elastomer is fully compressed and thus increase the compression ratio.

The pressure of the operating fluid and of the fluid being pumped are at or near equilibrium so that there will be little deformation of the elastomer during pumping. In addition the pump will stop on occurrence of a blockage or closed valve on either side of the pump.

The pump can be inserted directly into a fluid flow path and, as will be seen, there is a straight, axial flow path through the pump.

It will be seen that there are no sliding seals or glands in the pump described. Because of this there is no risk of gland failure leading to leakage of pumped fluid to atmosphere (which is important when pumping .toxic substances) or contamination of the pumped fluid by the operating fluid (which is important when pumping foodstuffs). Similarly, the pump can be worked satisfactorily when immersed in water. As there are no sliding parts, lubricants are not required and very little machining is necessary.

The construction of the pump in a number of sections allows it to be easily assembled and dismantled simplifying servicing, cleaning and replacement. By adding or changing sections the capacity of the pump can be varied as desired. The pump flow rate can also be varied to suit the viscosity and or solid content of the fluid pumped by controlling the cycle speed, the length of pumping stroke and the pressure of the operating fluid.

viscosity or suspension of high solids content.

The pump described above is self-priming and can run dry (that is, without any fluid being pumped) without damage.

FIG. 2 shows a section of a manual pump especially suitable as a priming pump, that is for filling a main pump with the fluid to be pumped prior to starting the main pump. In such an application the priming pump would be in series with, and upstream of, the main pump.

The pump is preferably of circular cross section and is formed at the junction of an inlet conduit 60 and an outlet conduit 61, each of which has a right-angled bend adjacent the junction so that the axis of the pump is perpendicular to the axis of the conduits. As inlet port 62 is provided in the end of the inlet conduit and has an associated nonreturn valve comprising a valve member 63 urged against the port mouth by a weak spring 64 attached to a fixed arm 65 within the conduit end. A compression plate 66 is supported downstream of, and coaxial with, the inlet by a first cylinder or tube unit of elastomer 67 attached to and held in the end face 68 of the inlet conduit and a coaxial rigid retaining ring 69 and a second similar, coaxial cylinder or tube unit 70 attached and held in the ring 69 and the face 71 of the compression plate 66. As with the fluid-operated pump, the series of cylinders may comprise one or more cylinders and the corresponding number of retaining rings. A main chamber 82 is thus formed between the compression plate and the inlet. The compression plate 66 has a central circular orifice 72 forming an outlet port. A nonreturn valve is associated with the outlet port and comprises a valve member 73 urged against the downstream mouth of the orifice by a weak spring 74 attached to a three-legged spider 75.

The pump is actuated on its drive stroke through a rod 76 extending from the center of the spider through a gland 77 in the outlet conduit 61 to a hand-operated lever 78 to which it is attached by a swivel joint 79. The lever fulcrum 80 is positioned much nearer to the swivel joint than the lever handgrip (not shown) to allow ample leverage and the lever is adapted to be folded at a joint 81 when not in use.

During a pumping cycle, as the lever is pressed down the compression plate 66 descends to compress the elastomer cylinders 67 and 70. During this stroke the inlet valve member 63 is closed and the outlet valve 73 is open so that fluid is exhausted from the main chamber 82 and passes between the legs of the spider to the outlet conduit 61. At the end of this exhaust stroke the lever is released and the compression plate is returned by the relaxation of the elastomer. During this stroke the outlet valve is closed and the inlet valve is opened so that the stroke is an intake stroke. The manual pump described can be adapted for mechanical operation by providing a mechanical (or electrical) drive to the rod 76 through a swashplate eccentric drive or other equivalent means.

lclaim:

l. A pump comprising,

a pump housing enclosing a main chamber,

inlet port means including a nonreturn valve in said housing communicating with said main chamber,

outlet port means including a nonreturn valve in said housing communicating with said main chamber,

a fixed surface within said chamber,

a slideable compression plate within said chamber slideable towards and away from said fixed surface,

a tube of elastomer extending in sealing engagement between said fixed surface and said compression plate,

power-transmission means connecting with said compression plate and adapted for connection to an external power source to transmit power to said plate and store energy in said tube by compression thereof during one stroke of a pumping cycle,

whereby said plate is returned during an alternate stroke of said pumping cycle by the energy stored in said tube, said pump housing comprising an internal cavity sealingly separated into said main chamber and an auxiliary chamber by said compression plate and said tube of elastomer, and said power transmission means comprising means in communication with said auxiliary chamber for the admission and release of an actuating fluid under pressure. 7

2. A pump as claimed in claim 1, wherein the compression plate is at the end of the tube remote from the main chamber so that the stroke in which the plate compresses the tube is an exhaust stroke and the return stroke in which the tube is relayed is an intake stroke. I

3. A pump as claimed in claim 2 wherein the compression plate has a central orifice for the passage of the fluid being pumped.

4. A pump as claimed in claim 3 wherein the main chamber, the compression plate and the tube have a common axis of symmetry and the inlet and outlet ports of the chamber and the orifice of the plate lie on this axis.

5. A pump as claimed in claim 4 wherein the main chamber of the pump has a cylindrical wall and the plate and tube are of annular cross section.

6. A pump as claimed in claim 1, wherein admission and release of said actuating fluid is regulated by a control valve unit and means is provided for operating said valve in response to the position of said compression plate.

7. A pump as recited in claim 6, wherein said control valve unit is operatively connected in circuit with a control switch, and an actuating rod for said switch is fixed to said compression plate.

8. A pump as claimed in claim 1 wherein said outlet port means is arranged in the center of said compression plate.

9. A pump comprising,

a pump housing enclosing a main chamber,

inlet port means including a nonreturn valve in said housing communicating with said main chamber,

outlet port means including a nonreturn valve in said housing communicating with said main chamber,

a fixed surface within said chamber,

a slidable compression plate within said chamber slidable towards and away from said fixed surface, said plate having a central orifice for the passage of fluid being pumped,

a tube of elastomer extending in sealing engagement between said fixed surface and said compression plate, said tube comprising a series of tube units of similar cross section connected by rigid retainer rings,

power-transmission means connecting with said compres-,

sion plate and adapted for connection to an external power source to transmit power to said plate and store energy in said tube by compression thereof during one stroke of a pumping cycle,

whereby said plate is returned during alternate stroke of said pumping cycle by the energy stored in said tube,

said compression plate being at the end of the tube remote from the main chamber so that the stroke in which the plate compresses the tube is an exhaust stroke and the return stroke in which the tube is relaxed is an intake stroke, and said main chamber, said compression plate and said tube having a common axis of symmetry with said inlet and outlet port means of the chamber and the orifice of said plate lying on this axis.

10. A pump as defined in claim 8, wherein said plate is displaced by fluid pressure during compression of said tube.

11. A pump as defined in claim 8, wherein mechanical means is connected for displacement of said plate.

12. A pump as claimed in claim 8, wherein said pump housing comprises an internal cavity and further comprising a fixed inner flange within said main chamber and an inner tube of elastomer within, and coaxial with, aforesaid tube of elastomer and extending between said inner flange and said plate, said tubes of elastomer together with said plate sealingly dividing said internal cavity into a main chamber and an auxiliary chamber with port means for entry and admission of operating fluid to said auxiliary chamber and said inner tube providing an axial path for fluid being pumped.

13. A pump as claimed in claim 12, wherein the wall of the auxiliary chamber opposite the compression plate is fixed.

14. A pump as claimed in claim 12, comprising an end wall portion including an axial intake valve, an end wall portion including an axial exhaust valve and one or more central sections held by tie rods between the end walls, each central section including the following parts arranged coaxially: an outer tubular portion having an inwardly directed flange at one end and having a port in its wall, an inner tubular portion having an outwardly directed flange at one end, coplanar with the flange of the outer portion, an annular cover plate in sealing contact at its outer and inner peripheries with the open ends of the outer and inner tubes and an annular compression plate within the cavity formed by the tubes and cover plates and spaced from the flanges by inner and outer tubular portions of elastomer to separate the cavity into a main chamber, in fluid connection with the said intake and exhaust valves and an auxiliary chamber in fluid connection with the said port for connection to a source of operating fluid.

15. A pump as claimed in claim 12 wherein said tubes are disposed so that, inoperation, one side of each tube is in contact with fluid being pumped and one side is in contact with operating fluid.

l6v A pump as claimed in claim 12 wherein a valve controlling admission and release of said operating fluid is actuated by switch operably connected to a compression plate.

17. in a pump, a cylinder unit comprising means defining a relatively stationary annular internal surface, an annular compression plate mounted for movement toward and away from said surface and an elastomeric tube structure surrounding a fluid space and extending between said surface and said plate with opposite ends thereof seated on said surface and said plate, inlet port means including a nonreturn valve permitting fluid flow only toward said space, outlet port means including a nonreturn valve permitting fluid flow only away from said space; and force producing means for displacing said plate toward said surface to axially compress said tube structure to reduce the volume of the space enclosed by said tube structure and effect discharge of fluid through said outlet port means, said compressed tube structure being energized when compressed and being adapted to act to displace said plate away from said surface when said force producing means is relaxed to expand said space and permit entry of fluid through said inlet port said force producing means comprising means defining a chamber on one side of said compression plate, passage means supplying fluid under pressure to said chamber, valve means in said passage means, and an actuator for said valve means operably connected to said compression plate whereby said valve means is actuated to exhaust said chamber at the end of each compression stroke of the plate and admit fluid under pressure into said chamber at the end of each return stroke of the plate. 

1. A pump comprising, a pump housing enclosing a main chamber, inlet port means including a nonreturn valve in said housing communicating with said main chamber, outlet port means including a nonreturn valve in said housing communicating with said main chamber, a fixed surface within said chamber, a slideable compression plate within said chamber slideable towards and away from said fixed surface, a tube of elastomer extending in sealing engagement between said fixed surface and said compression plate, power-transmission means connecting with said compression plate and adapted for connection to an external power source to transmit power to said plate and store energy in said tube by compression thereof during one stroke of a pumping cycle, whereby said plate is returned during an alternate stroke of said pumping cycle by the energy stored in said tube, said pump housing comprising an internal cavity sealingly separated into said main chamber and an auxiliary chamber by said compression plate and said tube of elastomer, and said power transmission means comprising means in communication with said auxiliary chamber for the admission and release of an actuating fluid under pressure.
 2. A pump as claimed in claim 1, wherein the compression plate is at the end of the tube remote from the main chamber so that the stroke in which the plate compresses the tube is an exhaust stroke and the return stroke in which the tube is relayed is an intake stroke.
 3. A pump as claimed in claim 2 wherein the compression plate has a central orifice for the passage of the fluid being pumped.
 4. A pump as claimed in claim 3 wherein the main chamber, the compression plate and the tube have a common axis of symmetry and the inlet and outlet ports of the chamber and the orifice of the plate lie on this axis.
 5. A pump as claimed in claim 4 wherein the main chamber of the pump has a cylindrical wall and the plate and tube are of annular cross section.
 6. A pump as claimed in claim 1, wherein admission and release of said actuating fluid is regulated by a control valve unit and means is provided for operating said valve in response to the position of said compression plate.
 7. A pump as recited in claim 6, wherein said control valve unit is operatively connected in circuit with a control switch, and an actuating rod for said switch is fixed to said compression plate.
 8. A pump as claimed in claim 1 wherein said outlet port means is arranged in the center of said compression plate.
 9. A pump comprising, a pump housing enclosing a main chamber, inlet port means including a nonreturn valve in said housing communicating with said main chamber, outlet port means including a nonreturn valve in said housing communicating with said main chamber, a fixed surface within said chamber, a slidable compression plate within said chamber slidable towards and away from said fixed surface, said plate having a central orifice for the passage of fluid being pumped, a tube of elastomer extending in sealing engagement between said fixed surfacE and said compression plate, said tube comprising a series of tube units of similar cross section connected by rigid retainer rings, power-transmission means connecting with said compression plate and adapted for connection to an external power source to transmit power to said plate and store energy in said tube by compression thereof during one stroke of a pumping cycle, whereby said plate is returned during alternate stroke of said pumping cycle by the energy stored in said tube, said compression plate being at the end of the tube remote from the main chamber so that the stroke in which the plate compresses the tube is an exhaust stroke and the return stroke in which the tube is relaxed is an intake stroke, and said main chamber, said compression plate and said tube having a common axis of symmetry with said inlet and outlet port means of the chamber and the orifice of said plate lying on this axis.
 10. A pump as defined in claim 8, wherein said plate is displaced by fluid pressure during compression of said tube.
 11. A pump as defined in claim 8, wherein mechanical means is connected for displacement of said plate.
 12. A pump as claimed in claim 8, wherein said pump housing comprises an internal cavity and further comprising a fixed inner flange within said main chamber and an inner tube of elastomer within, and coaxial with, aforesaid tube of elastomer and extending between said inner flange and said plate, said tubes of elastomer together with said plate sealingly dividing said internal cavity into a main chamber and an auxiliary chamber with port means for entry and admission of operating fluid to said auxiliary chamber and said inner tube providing an axial path for fluid being pumped.
 13. A pump as claimed in claim 12, wherein the wall of the auxiliary chamber opposite the compression plate is fixed.
 14. A pump as claimed in claim 12, comprising an end wall portion including an axial intake valve, an end wall portion including an axial exhaust valve and one or more central sections held by tie rods between the end walls, each central section including the following parts arranged coaxially: an outer tubular portion having an inwardly directed flange at one end and having a port in its wall, an inner tubular portion having an outwardly directed flange at one end, coplanar with the flange of the outer portion, an annular cover plate in sealing contact at its outer and inner peripheries with the open ends of the outer and inner tubes and an annular compression plate within the cavity formed by the tubes and cover plates and spaced from the flanges by inner and outer tubular portions of elastomer to separate the cavity into a main chamber, in fluid connection with the said intake and exhaust valves and an auxiliary chamber in fluid connection with the said port for connection to a source of operating fluid.
 15. A pump as claimed in claim 12 wherein said tubes are disposed so that, inoperation, one side of each tube is in contact with fluid being pumped and one side is in contact with operating fluid.
 16. A pump as claimed in claim 12 wherein a valve controlling admission and release of said operating fluid is actuated by switch operably connected to a compression plate.
 17. In a pump, a cylinder unit comprising means defining a relatively stationary annular internal surface, an annular compression plate mounted for movement toward and away from said surface and an elastomeric tube structure surrounding a fluid space and extending between said surface and said plate with opposite ends thereof seated on said surface and said plate, inlet port means including a nonreturn valve permitting fluid flow only toward said space, outlet port means including a nonreturn valve permitting fluid flow only away from said space; and force producing means for displacing said plate toward said surface to axially compress said tube structure to reduce the volume of the space enclosed by said tube structure and effect discharge of fluid through said ouTlet port means, said compressed tube structure being energized when compressed and being adapted to act to displace said plate away from said surface when said force producing means is relaxed to expand said space and permit entry of fluid through said inlet port said force producing means comprising means defining a chamber on one side of said compression plate, passage means supplying fluid under pressure to said chamber, valve means in said passage means, and an actuator for said valve means operably connected to said compression plate whereby said valve means is actuated to exhaust said chamber at the end of each compression stroke of the plate and admit fluid under pressure into said chamber at the end of each return stroke of the plate. 